Electronic system and heat dissipation device thereof

ABSTRACT

A heat dissipation device for an electronic component mounted on a circuit board includes a heat pipe and a fastening assembly. The heat pipe includes an evaporation section and a condensation section. The fastening assembly includes a retention plate and a wire clip. The retention plate includes a retaining portion abutting against the heat pipe, and two fastening portions located at opposite sides of the evaporation section of the heat pipe. The wire clip includes two abutting portions, a resisting portion interconnecting the abutting portions, and two locking arms extending outwardly from two outer ends of the abutting portions, respectively. The retaining portion and the resisting portion abut against the evaporation section of the heat pipe, the abutting portions abut against inner surfaces of the fastening portions, the locking arms are fastened to the circuit board, thereby mounting the retention plate with the heat pipe on the electronic component.

CROSS-REFERENCE TO RELATED APPLICATION

This application is related to a co-pending application entitled “HEATDISSIPATION DEVICE AND ELECTRONIC SYSTEM INCORPORATING THE SAME”(attorney docket number US31487), assigned to the same assignee of thisapplication and filed on the same date as this application.

BACKGROUND

1. Technical Field

The disclosure generally relates to heat dissipation, and particularlyto a heat dissipation device with a wire clip and an electronic systemincorporating the heat dissipation device.

2. Description of Related Art

It is well known that heat is generated by electronic components, suchas integrated circuit chips, during their operation. If the heat is notefficiently removed, the electronic components may suffer damage. Thus,heat dissipation devices are often used to cool the electroniccomponents.

In a typical computer system, more than one electronic component, suchas a central processing unit (CPU), a memory control hub (MCH), aninput/output (i/o) controller hub (ICH), and others, must be cooled.Since the electronic components are generally of different heights withtop surfaces thereof at different levels, a lone conventional heat sinkcannot make the required snug contact with the top surfaces of all thecomponents. Accordingly, a plurality of heat pipes is often employed toremove heat from the electronic components. However, there may not besufficient space in the electronic system to respectively secure theheat pipes on the electronic components via plural sets of screws. Inaddition, a tool, such as a screwdriver, is required when fastening thescrews. This complicates the assembly of the heat dissipation device.

What is needed, therefore, is an electronic system and a heatdissipation device thereof which can overcome the described limitations.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale, the emphasis instead placed upon clearlyillustrating the principles of the present embodiments. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the various views.

FIG. 1 is an assembled, isometric view of an electronic system inaccordance with one embodiment of the disclosure.

FIG. 2 is an exploded view of the electronic system of FIG. 1.

FIG. 3 is an enlarged view of a circled portion III of the electronicsystem shown in FIG. 2.

FIG. 4 is an enlarged, exploded view of a fastening assembly of theelectronic system of FIG. 1.

FIG. 5 is an isometric view of a fan disassembled from the electronicsystem of FIG. 1.

FIG. 6 is an inverted view of a heat spreader disassembled from a heatdissipation device of the electronic system of FIG. 1.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 2, an electronic system in accordance with oneembodiment of the disclosure is shown. The electronic system includes acircuit board 70, and a heat dissipation device mounted on the circuitboard 70. The circuit board 70 supports a first electronic component 72such as a CPU, and a second electronic component 74 such as an MCH, ICH,or other component. In the illustrative embodiment, the first electroniccomponent 72 generates more heat than the second electronic component 74during operation. The circuit board 70 defines therein a mounting hole76 near each corner of the first electronic component 72, and provides apair of clasps 78 near two diagonally opposite corners of the secondelectronic component 74. The heat dissipation device includes a firstbase 10 mounted on the first electronic component 72, a fan 20 locatedon the first base 10, a fin assembly 30 disposed beside the fan 20, asecond base mounted on the second electronic component 74, and a heatpipe assembly 50 thermally connecting the first base 10 and the secondbase with the fin assembly 30. The second base includes a heat spreader40, and a fastening assembly 60 fixing the heat spreader 40 onto thesecond electronic component 74.

The first base 10 includes a mounting rack 12, and a rectangular bottomplate 14 at a bottom of the mounting rack 12. The bottom plate 14 ismade of metal or metal alloy with a high heat conductivity coefficient,such as copper, copper-alloy, or other suitable material. The bottomplate 14 is attached to the first electronic component 72 of the circuitboard 70. The bottom plate 14 defines a plurality of parallel and spacedreceiving grooves 140 in a top surface thereof, for receiving the heatpipe assembly 50. The mounting rack 12 includes a rectangular top plate122 and four fixing legs 124 extending outwardly from four corners ofthe top plate 122, respectively. The top plate 122 defines a pluralityof parallel and spaced receiving grooves 1220 in a bottom surfacethereof, corresponding to the receiving grooves 140 of the bottom plate14. The top plate 122 arches at a middle thereof, corresponding to thereceiving grooves 1220. Two lateral sides of the top plate 122 arethinner than the arched portion of the top plate 122, for savingmaterial and reducing the weight of the first base 10. Each of thefixing legs 124 forms a mounting sleeve 1240 at a distal end thereof.Four fasteners 100 extend respectively through the mounting sleeves 1240of the fixing legs 124, for mounting the heat dissipation device on thecircuit board 70. Three of the fixing legs 124 each include a fixing arm126 extending outwardly from a lateral side thereof. The fixing arm 126is parallel to the receiving grooves 1220, and defines an internallythreaded sleeve 1260 at a distal end thereof.

The mounting rack 12 further includes a bracket 127 and an orientingportion 128, which are at opposite sides of the top plate 122,respectively. The bracket 127 is located away from the second electroniccomponent 74. The bracket 127 includes two extension arms 1272 extendingrespectively from outer circumferential surfaces of two adjacentmounting sleeves 1240 of the fixing legs 124, and a support plate 1274connecting two free ends of the extension arms 1272. A pair of tabs 1270extend perpendicularly upward from opposite ends of the support plate1274, respectively. The orienting portion 128 extends from the top plate122 toward the second electronic component 74, and is perpendicular tothe receiving grooves 1220. Referring also to FIG. 3, in the presentembodiment, the orienting portion 128 is an elongated rectangular plate.The orienting portion 128 includes an annular collar 1280 extendingperpendicularly upward from a distal end of a main body thereof. Thecollar 1280 defines an orienting hole 1282 therein.

The fan 20 is a centrifugal blower, and directs airflow toward the finassembly 30. The fan 20 includes a substantially rectangular housing 22.The housing 22 includes three ears 24 extending out from a bottom endthereof, corresponding to the fixing arms 126, respectively. Each of theears 24 defines a fixing hole 240 therethrough. A fastener 200 extendsthrough the fixing hole 240 of each ear 24 and is received in theinternally threaded sleeve 1260, the fasteners 200 thereby securing thefan 20 to the mounting rack 12 of the first base 10.

The fin assembly 30 is disposed on the support plate 1274 of the bracket127, adjacent to an air outlet (not shown) of the fan 20. The finassembly 30 includes a plurality of stacked fins 32. An air channel 36(shown in FIG. 6) is defined between every two adjacent fins 32. Each ofthe fins 32 is bent toward a lateral side thereof at one end away fromthe fan 20, with the air channel 36 between every two adjacent fins 32forming a corresponding shape, thereby deflecting the airflow from itsoriginal direction to generate turbulent airflow. This reduces airflowretention on outer surfaces of the fins 32, and enhances heat transferefficiency between the airflow and the fins 32. The fin assembly 30defines a plurality of parallel and spaced accommodating holes 34therein. The accommodating holes 34 extend through the fins 32. The tabs1270 of the bracket 127 abut against two outermost fins 32,respectively, preventing lateral sliding of the fin assembly 30.

The heat pipe assembly 50 includes a plurality of first heat pipes 52thermally connecting the first base 10 with the fin assembly 30, and asecond heat pipe 54 thermally connecting the heat spreader 40 with thefin assembly 30. The first heat pipes 52 are generally U-shaped, andeach includes an evaporation section 522, a condensation section 524,and an adiabatic section 526 interconnecting the evaporation section 522and the condensation section 524. The second heat pipe 54 is flattened,and includes an evaporation section 542, a condensation section 544, andan adiabatic section 546 interconnecting the evaporation section 542 andthe condensation section 544. The adiabatic section 546 of the secondheat pipe 54 is longer than the adiabatic section 526 of each first heatpipe 52. The condensation sections 524, 544 of the first and second heatpipes 52, 54 are received in the accommodating holes 34 of the finassembly 30, respectively. The evaporation sections 522 of the firstheat pipes 52 are received in cylindrical receiving holes cooperativelyformed by the receiving holes 140, 1220 of the top and bottom plates 14,122 of the first base 10, respectively. The evaporation section 542 ofthe second heat pipe 54 is attached to a top surface of the heatspreader 40. The adiabatic sections 526, 546 of the first and secondheat pipes 52, 54 are located beside the fan 20.

The heat spreader 40 is generally rectangular, and made of metal ormetal alloy which has a high heat conductivity coefficient, such ascopper, copper-alloy, or other suitable material. The heat spreader 40is attached to the second electronic component 74 of the circuit board70.

Referring also to FIG. 4, the fastening assembly 60 includes a retentionrack 62 mounting the evaporation section 542 of the second heat pipe 54on the heat spreader 40, and a wire clip 64 securing the heat spreader40 on the second electronic component 74. The retention rack 62 includesa retention plate 620, and a connecting portion 629 extending from theretention plate 620. The retention plate 620 is substantiallyrectangular, and defines an elongated opening 622 and a slot 624crossing the opening 622. The opening 622 extends diagonally along theretention plate 620, defining two substantially triangular portions ofthe retention plate 620. The slot 624 extends along an axisperpendicular to opposite lateral sides of the retention plate 620, anddivides each triangular portion of the retention plate 620 into twoportions. The opening 622 is wider than the evaporation section 542 ofthe second heat pipe 54, and the slot 624 is wider the wire clip 64.

The retention plate 620 includes a pair of retaining portions 626 and apair of fastening portions 628. The retaining portions 626 aresaddle-shaped. The retaining portions 626 span the opening 622, andinterconnect the triangular portions of the retention plate 620 dividedby the opening 622. The fastening portions 628 are substantiallysemicylindrical. Considered another way, the fastening portions 628 arein the form of arc-shaped bridges. The fastening portions 628 span theslot 624, and interconnect the portions of the retention plate 620divided by the slot 624. The retention plate 620 defines therein aplurality of rivet holes 627 beside the retaining portions 626, thefastening portions 628 and the connecting portion 629.

The connecting portion 629 is integrally formed with the retention plate620 as a single piece. That is, the retention plate 620 is a single,one-piece monolithic body which includes the connecting portion 629.Alternatively, the connecting portion 629 can extend integrally from theheat spreader 40, or be welded or riveted on the heat spreader 40. Theconnecting portion 629 is moveably connected with the orienting portion128 of the mounting rack 12. Namely, the retention rack 62 with theconnecting portion 629 is moveable in a permitted range with respect tothe orienting portion 128. In this embodiment, the connecting portion629 is laminar, and includes an oblique portion 6292 extending obliquelyupward from an edge of the retention plate 620, and a planar portion6294 extending horizontally from a top end of the oblique portion 6292.A thickness of the planar portion 6294 is less than a height of thecollar 1280 of the orienting portion 128. The planar portion 6294defines a connecting hole 6290 in a distal end thereof. A diameter ofthe connecting hole 6290 is greater than an outer diameter of the collar1280. The collar 1280 extends through the connecting hole 6290. Afastener 300 with a head 301 larger the connecting hole 6290 is receivedin the orienting hole 1282, for pivotally connecting the retention rack62 of the second base with the first base 10. The planar portion 6294 ofthe connecting portion 329 is located between the orienting portion 128and the head 301 of the fastener 300. Thus, the retention rack 62 is notonly moveable up and down, but is also rotatable horizontally withrespect to the collar 1280 of the first base 10.

The wire clip 64 is integrally made of a metal wire. The wire clip 64includes a middle member 642, and two locking arms 644 extendingperpendicularly and outwardly from opposite ends of the middle member642 toward generally opposite directions. Each of the locking arms 644forms a hook 6440 at a distal end thereof. The middle member 642includes two abutting portions 6422, and a resisting portion 6242interconnecting the abutting portions 6422. The resisting portion 6242arches from two adjacent ends of the abutting portions 6422. The twolocking arms 644 extending outwardly from two outer ends of the abuttingportions 6422 toward generally opposite directions, respectively. Thewire clip 64 is symmetrical with respect to the resisting portion 6242.

Referring also to FIGS. 5 and 6, the retention plate 620 of theretention rack 62 is riveted on the heat spreader 40 via the rivet holes627, with the evaporation section 542 of the second heat pipe 54 and theabutting portions 6422 of the wire clip 64 respectively received in theopening 622 and the slot 624 of the retention plate 620. The retainingportions 626 of the retention plate 620 and the resisting portion 6242of the wire clip 64 abut against a top surface of the evaporationsection 542 of the second heat pipe 54, and the abutting portions 6422of the wire clip 64 abut against inner surfaces of the fasteningportions 628. The locking arms 644 of the wire clip 64 are presseddownward until the hooks 6440 of the locking arms 644 clasp the clasps78 of the circuit board 70.

In the present heat dissipation device, the second heat pipe 54 ismounted on the second electronic component 74 via the retention plate620 and the wire clip 64. The wire clip 64 provides a steady lockingforce to connect the second heat pipe 54 firmly to the heat spreader 40,and the heat spreader 40 snugly contacts the second electronic component74 of the circuit board 70. Thus, screws and an associated tool are notrequired to stably mount the second heat pipe 54 on the secondelectronic component 74. This simplifies the heat dissipation device. Inaddition, a relatively smaller space is required during operation of thewire clip 64. This saves space in the electronic system. Furthermore,the retention rack 62 of the second base is movably connected with thefirst base 10 via the connecting portion 629. Therefore, the second heatpipe 54 thermally connecting the second base with the fin assembly 30does not deform easily during transport and assembly. Moreover, there isrequired moveable space between the retention rack 62 of the second baseand the first base 10 to meet production tolerances, such that a contactgap between the second heat pipe 54 and the heat spreader 40 is avoided.Thus, the heat dissipation efficiency of the heat dissipation device isenhanced.

It is to be understood, however, that even though numerouscharacteristics and advantages of the present embodiments have been setforth in the foregoing description, together with details of thestructures and functions of the embodiments, the disclosure isillustrative only, and changes may be made in detail, especially inmatters of shape, size, and arrangement of parts within the principlesof the invention to the full extent indicated by the broad generalmeaning of the terms in which the appended claims are expressed.

1. A heat dissipation device for an electronic component mounted on acircuit board, the heat dissipation device comprising: a heat pipecomprising an evaporation section and a condensation section; and afastening assembly comprising a retention plate and a wire clip, theretention plate comprising a retaining portion abutting against the heatpipe, and two fastening portions located at opposite sides of theevaporation section of the heat pipe, the wire clip comprising twoabutting portions, a resisting portion interconnecting the abuttingportions, and two locking arms extending outwardly from two outer endsof the abutting portions, respectively, the retaining portion and theresisting portion abutting against the evaporation section of the heatpipe, the abutting portions of the wire clip abutting against innersurfaces of the fastening portions, and the locking arms of the wireclip configured to be fastened to the circuit board thereby mounting theretention plate with the heat pipe on the electronic component.
 2. Theheat dissipation device of claim 1, wherein the retention plate definesan opening therein, and the evaporation section of the heat pipe isreceived in the opening.
 3. The heat dissipation device of claim 2,wherein the retention plate further comprises another retaining portionabutting against the heat pipe, and the two retaining portions of theretention plate span the opening and interconnect two portions of theretention plate divided by the opening.
 4. The heat dissipation deviceof claim 2, wherein the retention plate further defines a slot therein,the slot crosses the opening, the abutting portions of the wire clip arereceived in the slot, the fastening portions of the retention plate arerespectively located at opposite sides of the evaporation section of theheat pipe, and the fastening portions of the retention plate span theslot and interconnect portions of the retention plate divided by theslot.
 5. The heat dissipation device of claim 1, further comprising afin assembly thermally connecting the condensation section of the heatpipe.
 6. The heat dissipation device of claim 5, further comprising abase configured to be mounted on another electronic component, andanother heat pipe thermally connecting the fin assembly with the anotherelectronic component on which the base is mounted, the base pivotallyconnecting the retention plate.
 7. The heat dissipation device of claim6, wherein a connecting portion extends from the retention plate towardthe base, the base comprises an orienting portion extending toward theretention plate, and the orienting portion is pivotally connected withthe connecting portion.
 8. The heat dissipation device of claim 7,further comprising a fan mounted on the first base, the fin assemblybeing disposed at an air outlet of the fan, the fin assembly comprisinga plurality of stacked fins, each of the fins bent toward a lateral sidethereof at one end away from the fan.
 9. The heat dissipation device ofclaim 7, wherein the base comprises a bracket located away from theretention rack, and the fin assembly is disposed on the bracket.
 10. Theheat dissipation device of claim 9, wherein the bracket comprises twoextension arms extending from the base and a support plate connectingthe extension arms, and a pair of tabs extend up from opposite ends ofthe support plate and abut against two outermost fins of the finassembly, respectively.
 11. The heat dissipation device of claim 10,wherein the base further comprises a mounting rack and a bottom plate ata bottom of the mounting rack, the bottom plate is configured forattachment to the another electronic component on which the base ismounted, the mounting rack comprises a top plate and four fixing legsextending outwardly from four corners of the top plate, respectively,the top plate arches at a middle thereof, an evaporation section of theheat pipe which thermally connects the base is received between the topand bottom plates, each of the fixing legs forms a mounting sleeve at adistal end thereof, and the extension arms of the bracket extendrespectively from outer circumferential surfaces of two adjacentmounting sleeves of the fixing legs.
 12. The heat dissipation device ofclaim 1, wherein each of the locking arms forms a hook at a distal endthereof, and the hooks of the locking arms are configured for claspingthe circuit board.
 13. The heat dissipation device of claim 1, furthercomprising a heat spreader configured for thermally connecting theelectronic component; the retention plate and the evaporation section ofthe heat pipe attached to the heat spreader.
 14. An electronic system,comprising: a circuit board comprising an electronic component; a heatspreader thermally connecting the electronic component; a heat pipe; anda fastening assembly comprising a retention plate and a wire clip, theretention plate attached to the heat spreader, the retention platecomprising a retaining portion abutting against the heat pipe, and twofastening portions located at opposite sides of the heat pipe, the wireclip comprising two abutting portions, a resisting portioninterconnecting the abutting portions, and two locking arms extendingoutwardly from two outer ends of the abutting portions, respectively,the retaining portion and the resisting portion abutting against theheat pipe, the abutting portions of the wire clip abutting against innersurfaces of the fastening portions, and the locking arms of the wireclip fastened to the circuit board thereby mounting the heat pipe on theheat spreader and mounting the retention plate on the electroniccomponent.
 15. The electronic system of claim 14, wherein the retentionplate defines an opening therein, and a portion of the heat pipe isreceived in the opening and thermally contacts a top surface of the heatspreader.
 16. The electronic system of claim 15, wherein the retentionplate further comprises another retaining portion abutting against theheat pipe, the two retaining portions of the retention plate arerespectively located at opposite sides of the wire clip, and the tworetaining portions of the retention plate span the opening andinterconnect portions of the retention plate divided by the opening. 17.The electronic system of claim 14, wherein the retention plate furtherdefines a slot therein, the slot crosses the opening, the abuttingportions of the wire clip are received in the slot, and the fasteningportions of the retention plate span the slot and interconnect twoportions of the retention plate divided by the slot.
 18. The electronicsystem of claim 17, further comprising a fin assembly, another heat pipeand a base mounted on another electronic component, the heat pipes eachcomprising a condensation section received in the fin assembly, and anevaporation section respectively contacting the base and the retentionplate.
 19. The electronic system of claim 18, wherein the base comprisesan orienting portion extending toward the retention plate, the retentionplate comprises a connecting portion extending toward the base, and theconnecting portion is pivotally connected with the orienting portion.20. The electronic system of claim 14, wherein each of the locking armsforms a hook at a distal end thereof, the circuit board forms a pair ofclasps thereon, and the hooks of the locking arms clasp the clasps ofthe circuit board, respectively.